The purpose of this research is to examine the role of aquaporin channels in the peripheral gustatory system in mice. Responses to hypoosmotic stimuli and expression of aquaporin channels in taste receptor cells in two strains of inbred mice known to differ in taste preferences, C57BL/6ByJ and 129X/SvJ, will be characterized using electrophysiology, immunocytochemistry and molecular biology. Furthermore, behavioral responses to varying osmolarity will be assessed with and without the addition of different taste solutions using both brief access and long-term testing procedures. The specific role of aquaporin 5 will then be characterized using a knockout mouse model. Functional responses to hypoosmotic stimuli will be examined using electrophysiology. Expression of other members of the aquaporin family of channels will be described using immunocytochemistry, RT-PCR and real time PCR. Finally, basic taste preferences will be characterized in these animals as well as responses to changes in osmolarity with and without the addition of tastants using short-term and long-term testing methods. [unreadable] [unreadable]